Abstract: n this study, a series of heat treatment experiments were carried out on a batch of yellowish-green apatite for colour improvement, during which the effects of temperature, holding time and atmosphere on colour modification were investigated. The UV-Vis absorption spectra of the samples were collected and analyzed, both before and after heat treatment. The concentration by weight of trace elements was measured by laser ablation-inductively coupled plasma mass spectrometry. By comprehensive analysis of the results, the optimum parameters of this process was obtained and the colour improvement mechanism was described which can be provided as a reference for predicting the result of heat treatment.